This chapter assesses whether and how the rise in single parenthood influences child well-being. It first describes the types of family structure experienced by children in different OECD countries, and moves on to explain why single-parent family structure may influence child well-being. A meta-analysis follows, drawing on a large number of studies and comparing the effects of single parenthood across countries and by well-being dimensions. The penultimate section of the chapter discusses new techniques to identify causality in the literature, while the final section examines policy implications.